Punch press feeding mechanism



Jan. 29, 1957 w. H. SEASTROM PUNCH PRESS FEEDING MECHANISM 2 Sheets-Sheet 1 Filed April 2, 1954 WE-wszz. H 56 INVENTOR 1757' ROM BY W irrakwg/ Jan. 29, 1957 Filed April 2, 1954 w H. SEASTROM 2,779,590

PUNCH PRESS FEEDING MECHANISM 2 Sheets-Sheet 2 rVA/sfll. H 5545 Tea/14, INVEN TOR,

v a rroelvEy PUNCH PRESS FEEDING MECHANISM Wensil H. Seastrom, Glendale, Calif., assignor to Seastrom Manufacturing Co., a copartnership Application April 2, 1954, Serial No. 420,603

Claims. ((31. 271-25) This invention relates to a device for feeding workstock through a machine tool and has particular reference to stock feeding mechanism mountable on a punch press.

Conventional stock feeding devices for punch presses generally feed the stock ahead at uniform speed and the startings and stoppings of the feeding movements are so sudden that additional mechanism is required to insure correct feeding. It is also generally found that the feeding mechanism is positively actuated, the result being that anything interfering with the advance movement of the stock may and frequently will damage the feeding mechanism.

It is in view of the foregoing the object of the present invention to provide a stock feeding mechanism which is so designed and operated that the stock feeding movements commence and are completed so slowly that continuous, accurate feeding is assured without having to resort to additional movement checking devices. A further object is to provide a stock feeding mechanism which is capable of yielding in case the movement of the stock for some reason becomes blocked.

These and other objects of the invention together with the many advantageous features thereof are hereinafter fully described and drawing are hereto-fore appended in which a preferred form of the invention is illustrated.

In the drawings:

Fig. l is a front elevational view of a punch press to which the device of the invention is shown attached;

Fig. 2 is a perspective view on a larger scale, of the main portion of the device as it appears before mounting on the press;

Fig. 3 is a fragmentary view showing the relation of the feeding element of the device to the stock to be fed;

Fig. 4 is a cross sectional view of the left end of the device taken substantially on line 4-4 of Fig. 2; and

Figs. 5 and 6 illustrate the driving connections to the punch press.

The device of the invention, in the form illustrated in the drawings, is by a bracket 1 secured in position on one end surface of the bed A of a punch press, but it is to be understood that it may be adapted to any machine where an intermittent feed is required. A rectangular housing rises vertically from the upper surface of this bracket and on this housing is mounted a framing 2, the upper surface of which is grooved to form a guide for a carriage or slide 4. The latter is by a spring 5 urged outwardly into the position indicated in Fig. l of the drawings. A flexible connection including a chain 6 extends from the slide over a pulley '7, rising vertically therefrom. An annular head 8 is secured to the end thereof to ride on a crank 9 which, in turn, is rigidly mounted on the end of the power shaft B of the pres directly above the slide. A pawl 10 is pivotally hung on the inner end of theslide and a spring 11 urges the end of this pawl into contact with the stock C to be punched. The stock is first placed on the die D and it is manually advanced thereon into the housing below the framing 2, whereupon the press is started to lower the ram and the punch E to perform the atent ice punching operation. As the power shaft continues to rotate to force the punch into the die, it is seen that the crank 9 will commence to pull the chain 6 upwardly thereby to draw the slide along in its guide to move the hooked end 12 of the pawl into registration with a punched perforation F of the stock, against the tension of the spring 5. Upon continued rotation of the shaft to complete the upward movement of the ram and punch, it is found that the chain commences to s'lacken thereby to permit the spring to draw the slide and pawl in the opposite direction and in moving to feed the stock forward on the die. The operation of the. press may now be continued until the required number of perforations have been punched in the stock. The hoolced end 12 of the pawl will during the operation of the press continue to feed the stock along with unvarying precision.

The distance the pawl is to feed the stock forward will, of course, depend on the required perforation spacing thereof and means must be provided for regulating the movement of the slide 4 to obtain correct spacing. The crank 9 is for this purpose made adjustable. It is also necessary to adjust the slide t correctly to check advance movement of the stock. I have for this purpose shown a bracket 15 mounted on the extension 16 of the guide in which the slide 4 is seated. A screw 17 is shown seated in this bracket in continued axial alinement with the slide and this screw may be manually rotated in the bracket to determine the limit of slide advance movement. When the threads of the screw are very fine, substantially like the threads of a micrometer, it is seen that close adjustment of the slide may readily be obtained. Axial adjustment of the slide to bring the end 12 of the pawl into correct registration with the punched perforation of the stock is obtained by varying the length of the flexible connections. The latter is for this purpose shown fitted with the turnbuckle 2d engaging threaded extensions 21, 22 of the head 9 and of the end of the chain, respectively.

A cylindrical punch is for the sake of simplicity and clearness shown coaxial with the center of the ram, but punches of other shapes and differently positioned may, of course, be used. The above described means of axial adjustment of the slide will take care of any variation in the shape and position of the punch in the direction of movement of the stock. But since the position and shape of the punch also may vary transversely, it becomes necessary to provide means for correspondingly adjusting the framing 2. The latter is for this purpose shown seated in a transverse guide 24 of the bracket 1 and it is locked in adjusted position therein by means of a wing nut 25 engaging a stud 25 downwardly extending from the framing through an elongated perforation of the bracket (not shown).

The crank 9 is for the purpose of fine adustment constructed in the manner best shown in Fig. 6 of the drawings. An annular base 3 is by a screw 31 clamped in position on the end of the power shaft B and this base is diametrically grooved to support therein a bar 32. A number of threaded perforations are cut through this bar of a size to receive a stud 3-5 on which the annular head 8 is mounted to rotate. By adjustment of the bar in the base and by seating the bolt 34 in any desired perforation 33, it is possible to obtain very fine adjustment of the extent of movement of the slide 4. Blocks 35, 36 are seated in grooves of the base and they are by screws 39 pressed against the bar 32 to clamp the bar in position.

It is seen from the foregoing description that I have provided a very simple device which will feed material through a press with unvarying precision and which may easily and correctly be adjusted to any required spacing and location of the perforations punched in the material fed through the press. The spring 5 can be of such length thatthe tension thereof may remain substantially uniform during the material feeding operation. The great advantage of employing the crank 9 to control the movement of the slide is that the pull on the material commences slowly, accelerates and gradually and slowly comes to a stop. In other press feeding devices that have come to my attention, the feeding starts and stops so suddenly that additional means must be added to insure exact step by step movement. Another great advantage is that the spring is capable of yielding in case for some reason advance movement of the stock is blocked. But while I have herein described a preferred form of the invention it is to be understood that modification of arrangements, proportions and shapes, within the scope of the claims hereto appended, may be introduced without departing from the spirit of the invention.

I claim:

1. A punch press stock feeding attachment comprising a bracket fastened to the end surface of the press bed, a rectangular housing rising from the upper surface of said bracket, 21 grooved framing mounted on said housing, a slide movable in the groove of the framing, a stock feeding pawl on the slide, resilient means urging movement of the slide and pawl in stock feeding direction, means for limiting stock feeding movement of the slide, a crank on the power shaft of the press directly above the slide, and adjustable connections from the slide to the crank to draw the slide in the opposite direction against the ten sion of said resilient means.

2. A punch press stock feeding attachment comprising a bracket fastened to the end surface of the press bed, a rectangular housing rising from the upper surface of said bracket, a grooved framing mounted on said housing, a slide movable in the groove of the framing, a stock feeding pawl on the slide, resilient means urging movement of the slide and pawl in stock feeding direction, adjustable means for limiting stock feeding movement of the slide, a crank on the power shaft of the press directly above the slide, and adjustable connections from the slide to the crank to draw the slide in the opposite direction against the tension of said resilient means.

3. A punch press stock feeding attachment comprising, a grooved framing mounted on the end surface of the press bed and rising above the surface of the bed, a slide movable in the groove of the framing, a stock feeding pawl on the slide, resilient means urging movement of the slide and pawl in stock feeding direction, a grooved base on the power shaft of the press, a bar diametrically seated for lengthwise adjustment in the groove of the base, means for locking the bar in adjusted position in the base, a stud projecting from the bar, and connections rising from the slide to the said stud to draw the slide in the opposite direction against the tension of said resilient means.

4. A punch press stock feeding attachment comprising, a bracket mounted onthe end surface of the press bed, a grooved framing rising from the upper surface of said bracket, a slide movable in the groove of the framing, a stock feeding pawl on the slide, resilient means urging movement of the slidev and pawl in stock feeding direc tion, a grooved base on the power shaft of the press, a bar diametrically seated for lengthwise adjustment in the groove of the base, the bar having a series of threaded perforations therethrough, means for locking the bar in adjusted position in the base, a stud seatable in any one of said perforations of the bar, and connections rising from the slide to the said stud to draw the slide in the op posite direction against the tension of said resilient means upon rotation of the shaft.

5.. A punch press feeding attachment comprising, a bracket mounted on the end surface of the press bed, a grooved framing rising from the upper surface of said bracket, the framing being transversely adjustable on the bracket, a slide movable in the groove of the framing, a stock feeding pawl on the slide, resilient means urging movement of the slide and pawl in stock feeding direction, a grooved base on the power shaft of the press, a bar diametrically seated for lengthwise adjustment in the groove of the base, the bar having a series of threaded perforations therethrough, means for locking the bar in adjusted position in the base, a stud seatable in any one of said perforations of the bar, and connections rising from the slide to the said stud to draw the slide in the opposite direction against the tension of said resilient means upon rotation of the shaft.

References Cited in the file of this patent UNITED STATES PATENTS 562,222 Granger June 16, 1896 1,124,368 White Jan. 12, 1915 1,208,084- Bosch Dec. 12, 1916 1,458,339 Hancock June 12, 1923 1,481,332 Stock Jan. 22, 1924 

